68 Tri Power Vette

[Jack Enright]

Hi:

I am looking into buying a 1968 Corvette roadster with a 427 tri power engine with four speed.

The VIN matches the ID number on the engine pad, and the engine code is IO, which I thought signified a 427-400hp tri-power engine with automatic transmission. However, the car has a four speed. It looks factory, the current owner bought the car in 1972 from the original owner, and he swears it is all original.

I came across data on one website that indicated IO (on the engine pad) could signify 427-400hp (Vette with automatic)or 427-425 hp (Chevrolet with special high performance with four speed). Did Vette also use the 425hp special high performance engine?

Any thoughts or light that you could shed on the issue would be appreciated.

Thanks for your help,

Jack Enright

[Chuck G.]

Re: 68 Tri Power Vette

Assuming it's the original engine, somebody converted it to a 4 speed sometime in a past life. Chuck

[Tony Merendino]

Re: 68 Tri Power Vette

You are correct IO is the code for 427 400HO 3x2 with auto. IQ is the code for 427/390 with a quadrajet and auto. Either way it appearsd that someone dropped a 4 speed into that car in its early life.

[Ralph S.]

Re: 68 Tri Power Vette

Does the transmission crossmember bolt to the frame. if it does, it was an automatic trans car.

[Joe L.]

Re: 68 Tri Power Vette

Ralp and Jack-----

Yup, that's the easiest way to confirm what transmission was originally installed in the car for any 68-78 Corvette. Assuming that the frame is original to the car, if the transmission crossmember is bolted to the frame at the ends, the car was an original automatic transmission-equipped car. If it is welded to the frame at the ends, it was originally a manual transmission car. Period. No matter what anyone says or "swears" about the car.